The National Library of Medicine (NLM) is a national and international resource for biomedical information. Through use of the Library's computer-based medical literature Analysis and Retrieval System (MEDLARS), users within the biomedical community receive timely, accurate and comprehensive bibliographic information. In addition to providing online retrieval services, MEDLARS is used for preparing and photocomposing bibliographic publications. INDEX MEDICUS, a monthly subject/author guide to articles in almost 3,000 biomedical journals, is the most well known of these. INDEX MEDICUS is used a s a primary reference source by medical institutions and health care professions throughout the world. The objective of this project is to obtain editing, keyboarding, proofreading and online error correction of data that will enter MEDLARS. This project requires the processing of 400,000 biomedical articles and 300,000 abstracts during the contract period.